Members of parliament disagree about all sorts of things. Yet they frequently share two strongly held beliefs. One is that MPs in general, and the one to whom you happen to be speaking to at the time in particular, work hard and virtuously on behalf of their constituents and the public good. The other is that their exposure to and experience of the real world equips them with an unusually fine-tuned sense of public opinion and the limits of the possible. Much of the time, these two instincts are compatible, often admirably and productively so. In too many cases, however, MPs still remain at risk of setting their self-esteem and their pragmatism on a collision course, especially over the issue of parliamentary expenses.

Ipsa is clearly right to hold the new review. Equally clearly, there may need to be some changes in the expenses regime as a result of it. But MPs would make a foolish error if they interpret the holding of the Ipsa review as a sign of weakness and if they tried to use it as an opportunity to bring back anything approaching the old allowances largesse. Even to make the attempt would be dangerous in the present mood. Up and down the land, other employees in the public sector are being forced to tighten belts in every way. As ever, there are some exceptions, but in most cases the austerity process involves widespread sacrifice.

MPs would be wrong in principle and utterly mad in practice to test the public's patience by claiming to be a specially deserving case. In many respects, the current culture in which MPs are presumed guilty and venal is not just unfair but destructive. The sooner MPs win back respect and trust, the better. But there is still, as Ipsa said yesterday, a long way to go. MPs must get real. Changes at the margins of the parliamentary expenses system are one thing. Wholesale loosening and recasting of the new system is simply not on.